Butterfly valves are shutoff elements widely used in water resources engineering. In contrast to slide gate valves, butterfly valves are extremely compact and, especially in nominal widths larger than DN 300, require considerably less mounting space. Therefore, piping systems with nominal widths from approximately DN 300 are most often equipped with butterfly valves. Butterfly valves generally comprise a valve disk, which is mounted to swivel about an axis of rotation inside a housing and which is torsionally rigidly connected to a drive shaft that is pivotably mounted inside the housing. In the prior art valve disks, the drive shaft is often connected to the valve disk by means of splined shaft couplings or polygon couplings. Although this ensures a secure connection with good force transmission, the manufacture of shaft/hub couplings of this type is complex and, accordingly, entails high costs.
U.S. 2012/0248361 A1 discloses a prior art butterfly valve comprising a valve disk swivel mounted about an axis of rotation inside a housing, and having a disk-shaped valve body and hubs for receiving a drive shaft, which is pivotably mounted inside the housing; and a bearing bolt on the opposite side of the drive shaft. In this prior art butterfly valve, both the drive shaft and the bearing bolt are torsionally rigidly connected to the valve disk by means of a tapered pin.